The disclosure is directed to a mill, such as a mill used to perform a Z-axis plunging operation, and a method of using the mill to perform the plunging operation.
It is known to use a compressor in the oil and gas industry. For example, the compressor can be used to pressurize oil or gas flowing through the pipeline. It is also known to use an impeller blade with a relatively complex geometry in the compressor, to achieve desired flow characteristics of the fluid in the compressor. A known mill can be used to manufacture the impeller blade by translating the mill along an X-axis and a Y-axis while plunging the mill along the Z-axis. This is referred to as a Z-axis plunging operation or plunge milling.
FIG. 1A is a side view of a known high speed steel (HSS) mill 100, and FIG. 1B is a frontal view of the known mill 100. The known mill 100 includes top cutting teeth 151 on a top surface of a cutting head 150, which is connected to a shaft 160 that extends along the Z-axis. By this arrangement, the cutting head 150 rotates as the shaft 160 is rotated by a motor around the Z-axis. Rotation of the cutting head 150 results in the removal of material, such as from an impeller blade, by the top cutting teeth 151. FIG. 2 shows a known insert mill 102 having teeth 171 that are attached with screws to a shaft 173.
Using the known mills 100 and 102 to manufacture the impeller blade can provide some advantages compared to manufacturing the blade by other methods. For example, the known mills 100 and 102 can be used to manufacture geometries that would be difficult or impossible to manufacture by other methods. Further, the known mills 100 and 102 can remove a relative large volume of material in a relatively short period of time.
There are disadvantages, however, resulting from using the known mills 100 and 102. For example, when an arrangement that includes the known mills 100 or 102 has a relatively large kit length, for example, the length from the head of the mill to the motor, the known mills 100 and 102 can deflect or vibrato during material removal from the impeller blade. This deflection can result in the blade having inaccurate geometries. The deflection can also result in an unsatisfactory finish on a surface of the impeller blade, as well as excessive noise during manufacturing of the blade.